Magnetic signal



Oct. 3, 1944. 'CARR 'LL 2,359,546

MAGNET I C S IGNAL Filed Feb. 5, 1943 FIG.3.

INVENTOR. laws It. 6310 9044 Patented Oct. 3, 1944 MAGNETIC SIGNAL Louis W. Carroll, New York, N. Y., assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application February 5, 1943, Serial No. 474,789-

Claims.

This invention relates to improvements in magnetic signals as used, for example, in connection with central telephone office switchboards.

One of the objects of the invention is the provision of a less expensive design for magnetic signals as compared with signals or drops at present used on telephone switchboards.

Another object is the provision of a more efficient signal electrically, as well as a more positive visual signal than the present shutter type of drop.

The invention contemplates, in combination with an electromagnet, the use of an armature to which is attached a target having a white or distinguishing color. The armature is supported on an axis and is provided with a counterweight for so adjusting the balance that the armature will normally remain in an unoperated position. Provision is also made for retaining, by means of friction, the signal in an operated position until such time as it may be restored by mechanical means to its normal position.

The signal mounting is provided with a Window, behind which the target is displayed when in an operated position. The mounting is arranged for mounting the usual spring jacks used in connection with the line signal.

The above and other objects and features of the invention will be better understood from a reading of the following detailed description taken in conjunction with the accompanying drawing, in which Fig. 1 is a profile or side view of the combined jack and signal with a sectional view of the mounting; Fig. 2 is a front view of the mounting showing the window and jack sleeve; Fig. 3 is a schematic circuit of the operating coil and night alarm circuit.

In Fig. 1, I is the signal mounting, 2 is the usual spring jack, 3 is the electro-magnet, 4 is the return pole piece provided with a bearing or pivot I 9 for the armature, 5 is the armature carrying target 6, 1 is the night alarm spring arranged for making contact with armature 5 at point 8, 9 is the restoring spring arranged to be operated in conjunction With the jack spring by means of the insulated stud I0, II is the counterweight eccentrically mounted on armature 5 by means of rivet l2 in such manner that the weight may be adjusted toward or away from the fulcrum of the armature. The armature 5 is provided with a right-angle extension M which in its attracted position frictionally engages the end 8 of spring 1.

The operation of the signal is as follows: When the sub-station signals the central ofilce by means of a magneto or other source of current at the sub-station, the current thus flowing over jack spring contacts l6, l1 and through the winding of the electro-magnet 3 creates a magnetic field which causes the armature 5 to assume a horizontal position due to its attraction toward pole piece 13. The armature now being in a horizontal position, the right angle extension l4 makes contact With night alarm spring 1 at point 8, the friction of such contact being sufiicient to retain the armature in the operated position, thus displaying the target 6 at the Window l5, shown in Fig. 2, and closing a circuit for the night alarm from ground over the return pole piece 4, armature extension l4 and night-alarm spring 1. On the insertion of the operators plug, the contacts [6 and l! of the jack springs are opened thus disconnecting the winding of the electro-magnet 3 from the line circuit; and at the same time an upward movement of restoring spring 9 is produced through the medium of insulated stud ID. This movement in turn restores the armature to its normal position due to tip l8 of restoring spring 9 striking the armature in an upward direction thus disengaging the armature from its frictional contact with the night alarm spring 7 at point 8.

The invention is not limited to the precise details illustrated in the drawing and modifications may be made coming within the scope of the invention as defined by the appended claims.

What is claimed is:

1. A magnetic signal comprising an electromagnet, a counterbalanced armature mounted on a pivot and carrying a target, means for displaying said target when said armature is in its attracted position, and friction means for retaining said armature in its attracted position.

2. A magnetic signal comprising an electromagnet, a counterbalanced armature mounted on a pivot, a target, means for displaying said tar-get when said armature is in its attracted position, a contact spring, and an extension on said armature shaped to make contact with said spring in the attracted position of said armature and frictionally to retain said armature in its attracted position.

3. A magnetic signal comprising an electromagnet, a counterbalanced armature mounted on a pivot and carrying a target, means for displaying said target when said armature is in its attracted position, friction means for retaining said armature in its attracted position, a spring jack, and means for restoring said armature to its unattracted position when a plug is inserted into said jack.

4. A combined magnetic signal and line jack for a telephone switchboard, comprising an electromagnet, a counter-balanced armature mounted on a pivot, a target, jack springs having normally closed contacts connected to said electromagnet, means for displaying said target when said armature is in its attracted position, a night alarm spring, an extension on said armature shaped to frictionally engage said night alarm spring and hold said armature in its attracted position, and means actuated by the insertion of a plug into said line jack for restoring said armature to its unattracted position.

5. A combined magnetic signal and line jack according to claim 4 in which said last-mentioned means comprises a spring operable by'the insertion of a plug into said jack for tilting said armature into its unattracted position.

6. A combined magnetic signal and line jack according to claim 4 wherein said armature is provided with a counterweight eccentrically mouted whereby its distance from the pivotal point of the armature may be adjusted.

'7. A combined magnetic signal and line jack comprising a frame, an electromagnet mounted on said frame, a return pole piece, an armature pivotally mounted on said return pole piece carrying at one end an annunciator target and at the other end a counterweight, a spring, an extension on said armature so shaped that it frictionally engages said spring and retains said armature in its attracted position, a spring associated with said line jack, and a projection on said last-mentioned spring for restoring said armature to its unattracted position.

8. A magnetic signal comprising an electromagnet, a counter-balanced armature mounted upon a pivot and carrying at one end with an annunciator target, means, for displaying said target when said electromagnet is energized, and means for restoring said armature to its unattracted position.

9'. A magnetic signal according to claim 8 wherein friction means is provided for retaining said armature in its attracted position after said electromagnet is deenergized.

10. A magnetic. signal according to claim 8 further comprising a line jack and wherein said last-mentioned means comprises spring mechanicall-y associated with said line jack and arranged to tilt saidarmature into its unattracted position when a plug is inserted into said jack.

LOUIS W. CARROLL 

